package cn.actoncode.boot.framework.common.http.apache;

import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.apache.http.HttpHost;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.HttpRequestRetryHandler;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.config.SocketConfig;
import org.apache.http.conn.ConnectionKeepAliveStrategy;
import org.apache.http.conn.HttpClientConnectionManager;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.TrustStrategy;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.ssl.SSLContexts;

import javax.annotation.concurrent.NotThreadSafe;
import javax.net.ssl.SSLContext;
import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * httpclient 连接管理器
 *
 * @author bin
 */
@Slf4j
@Data
@NotThreadSafe
public class ActoncodeDefaultApacheHttpClientBuilder implements ApacheHttpClientBuilder {
    private final AtomicBoolean prepared = new AtomicBoolean(false);

    /**
     * 获取链接的超时时间设置
     * <p>
     * 设置为零时不超时,一直等待.
     * 设置为负数是使用系统默认设置(非3000ms的默认值,而是httpClient的默认设置).
     * </p>
     */
    private int connectionRequestTimeout = -1;

    /**
     * 建立链接的超时时间,默认为5000ms.由于是在链接池获取链接,此设置应该并不起什么作用
     * <p>
     * 设置为零时不超时,一直等待.
     * 设置为负数是使用系统默认设置(非上述的5000ms的默认值,而是httpclient的默认设置).
     * </p>
     */
    private int connectionTimeout = 5000;
    /**
     * 默认NIO的socket超时设置,默认60000ms.
     */
    private int soTimeout = 60000;
    /**
     * 空闲链接的超时时间,默认60000ms.
     * <p>
     * 超时的链接将在下一次空闲链接检查是被销毁
     * </p>
     */
    private int idleConnTimeout = 60000;
    /**
     * 检查空间链接的间隔周期,默认60000ms.
     */
    private int checkWaitTime = 60000;
    /**ad
     * 每路的最大链接数,默认10
     */
    private int maxConnPerHost = 10;
    /**
     * 最大总连接数,默认50
     */
    private int maxTotalConn = 50;
    /**
     * 自定义httpclient的User Agent
     */
    private String userAgent;

    /**
     * 自定义重试策略
     */
    private HttpRequestRetryHandler httpRequestRetryHandler;

    /**
     * 自定义KeepAlive策略
     */
    private ConnectionKeepAliveStrategy connectionKeepAliveStrategy;

    private final HttpRequestRetryHandler defaultHttpRequestRetryHandler = (exception, executionCount, context) -> false;

    private SSLConnectionSocketFactory sslConnectionSocketFactory = SSLConnectionSocketFactory.getSocketFactory();
    private final PlainConnectionSocketFactory plainConnectionSocketFactory = PlainConnectionSocketFactory.getSocketFactory();
    private String httpProxyHost;
    private int httpProxyPort;
    private String httpProxyUsername;
    private String httpProxyPassword;
    /**
     * 闲置连接监控线程
     */
    private ActoncodeIdleConnectionMonitorThread actoncodeIdleConnectionMonitorThread;
    /**
     * 持有client对象,仅初始化一次,避免多service实例的时候造成重复初始化的问题
     */
    private CloseableHttpClient closeableHttpClient;

    private ActoncodeDefaultApacheHttpClientBuilder() {
    }

    public static ActoncodeDefaultApacheHttpClientBuilder get() {
        return SingletonHolder.INSTANCE;
    }

    @Override
    public ApacheHttpClientBuilder httpProxyHost(String httpProxyHost) {
        this.httpProxyHost = httpProxyHost;
        return this;
    }

    @Override
    public ApacheHttpClientBuilder httpProxyPort(int httpProxyPort) {
        this.httpProxyPort = httpProxyPort;
        return this;
    }

    @Override
    public ApacheHttpClientBuilder httpProxyUsername(String httpProxyUsername) {
        this.httpProxyUsername = httpProxyUsername;
        return this;
    }

    @Override
    public ApacheHttpClientBuilder httpProxyPassword(String httpProxyPassword) {
        this.httpProxyPassword = httpProxyPassword;
        return this;
    }

    @Override
    public ApacheHttpClientBuilder httpRequestRetryHandler(HttpRequestRetryHandler httpRequestRetryHandler) {
        this.httpRequestRetryHandler = httpRequestRetryHandler;
        return this;
    }

    @Override
    public ApacheHttpClientBuilder keepAliveStrategy(ConnectionKeepAliveStrategy keepAliveStrategy) {
        this.connectionKeepAliveStrategy = keepAliveStrategy;
        return this;
    }

    @Override
    public ApacheHttpClientBuilder sslConnectionSocketFactory(SSLConnectionSocketFactory sslConnectionSocketFactory) {
        this.sslConnectionSocketFactory = sslConnectionSocketFactory;
        return this;
    }

    public ActoncodeIdleConnectionMonitorThread getActoncodeIdleConnectionMonitorThread() {
        return this.actoncodeIdleConnectionMonitorThread;
    }

    private synchronized void prepare() {
        if (prepared.get()) {
            return;
        }
        Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory>create()
                .register("http", this.plainConnectionSocketFactory)
                .register("https", this.sslConnectionSocketFactory)
                .build();

        @SuppressWarnings("resource")
        PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(registry);
        connectionManager.setMaxTotal(this.maxTotalConn);
        connectionManager.setDefaultMaxPerRoute(this.maxConnPerHost);
        connectionManager.setDefaultSocketConfig(
                SocketConfig.copy(SocketConfig.DEFAULT)
                        .setSoTimeout(this.soTimeout)
                        .build()
        );

        this.actoncodeIdleConnectionMonitorThread = new ActoncodeIdleConnectionMonitorThread(
                connectionManager, this.idleConnTimeout, this.checkWaitTime);
        this.actoncodeIdleConnectionMonitorThread.setDaemon(true);
        this.actoncodeIdleConnectionMonitorThread.start();

        HttpClientBuilder httpClientBuilder = HttpClients.custom()
                .setConnectionManager(connectionManager)
                .setConnectionManagerShared(true)
                .setSSLSocketFactory(this.buildSSLConnectionSocketFactory())
                .setDefaultRequestConfig(RequestConfig.custom()
                        .setSocketTimeout(this.soTimeout)
                        .setConnectTimeout(this.connectionTimeout)
                        .setConnectionRequestTimeout(this.connectionRequestTimeout)
                        .build()
                );

        // 设置重试策略，没有则使用默认
        httpRequestRetryHandler = httpRequestRetryHandler == null ? defaultHttpRequestRetryHandler : httpRequestRetryHandler;
        httpClientBuilder.setRetryHandler(httpRequestRetryHandler);

        // 设置KeepAliveStrategy，没有使用默认
        if (connectionKeepAliveStrategy != null) {
            httpClientBuilder.setKeepAliveStrategy(connectionKeepAliveStrategy);
        }

        if (StringUtils.isNotBlank(this.httpProxyHost) && StringUtils.isNotBlank(this.httpProxyUsername)) {
            // 使用代理服务器 需要用户认证的代理服务器
            CredentialsProvider provider = new BasicCredentialsProvider();
            provider.setCredentials(new AuthScope(this.httpProxyHost, this.httpProxyPort),
                    new UsernamePasswordCredentials(this.httpProxyUsername, this.httpProxyPassword));
            httpClientBuilder.setDefaultCredentialsProvider(provider);
            httpClientBuilder.setProxy(new HttpHost(this.httpProxyHost, this.httpProxyPort));
        }

        if (StringUtils.isNotBlank(this.userAgent)) {
            httpClientBuilder.setUserAgent(this.userAgent);
        }

        this.closeableHttpClient = httpClientBuilder.build();
        prepared.set(true);
    }

    private SSLConnectionSocketFactory buildSSLConnectionSocketFactory() {
        try {
            SSLContext sslcontext = SSLContexts.custom()
                    //忽略掉对服务器端证书的校验
                    .loadTrustMaterial(new TrustStrategy() {
                        @Override
                        public boolean isTrusted(X509Certificate[] chain, String authType) throws CertificateException {
                            return true;
                        }
                    }).build();

            return new SSLConnectionSocketFactory(
                    sslcontext,
                    new String[]{"TLSv1"},
                    null,
                    SSLConnectionSocketFactory.getDefaultHostnameVerifier());
        } catch (NoSuchAlgorithmException | KeyManagementException | KeyStoreException e) {
            log.error("构建SSL连接工厂时发生异常！", e);
        }

        return null;
    }

    @Override
    public CloseableHttpClient build() {
        if (!prepared.get()) {
            prepare();
        }
        return this.closeableHttpClient;
    }

    /**
     * DefaultApacheHttpClientBuilder 改为单例模式,并持有唯一的CloseableHttpClient(仅首次调用创建)
     */
    private static class SingletonHolder {
        private static final ActoncodeDefaultApacheHttpClientBuilder INSTANCE = new ActoncodeDefaultApacheHttpClientBuilder();
    }

    public static class ActoncodeIdleConnectionMonitorThread extends Thread {
        private final HttpClientConnectionManager connMgr;
        private final int idleConnTimeout;
        private final int checkWaitTime;
        private volatile boolean shutdown;

        public ActoncodeIdleConnectionMonitorThread(HttpClientConnectionManager connMgr, int idleConnTimeout, int checkWaitTime) {
            super("ActoncodeIdleConnectionMonitorThread");
            this.connMgr = connMgr;
            this.idleConnTimeout = idleConnTimeout;
            this.checkWaitTime = checkWaitTime;
        }

        @Override
        public void run() {
            try {
                while (!this.shutdown) {
                    synchronized (this) {
                        wait(this.checkWaitTime);
                        this.connMgr.closeExpiredConnections();
                        this.connMgr.closeIdleConnections(this.idleConnTimeout,
                                TimeUnit.MILLISECONDS);
                    }
                }
            } catch (InterruptedException ignore) {
            }
        }

        public void trigger() {
            synchronized (this) {
                notifyAll();
            }
        }

        public void shutdown() {
            this.shutdown = true;
            synchronized (this) {
                notifyAll();
            }
        }
    }
}
